Ionic liquids (ILs) are currently the focus of a rapidly growing number of studies in materials science. Within the present specification “ionic liquid” includes those salts whose melting point is below 100° C. Within this context salts that are liquid at room temperature are called room-temperature ionic liquids and typically comprise an organic cation. ILs were first studied for electrometallurgy, high-temperature batteries and organic synthesis, for their wide electrochemical windows, ionic conductivity, good chemical and thermal stability, very low volatility, solvent properties and broad liquid range over room temperature. Since then, their design has been rationalized for specific tasks in organic synthesis and catalysis, in green chemistry, and in energy production and storage as electrolytes. Increasingly, numerous studies are currently stemming from some early hints regarding their use in materials science, for instance as lithium batteries, supercapacitors, solar and fuel cells.
Besides the goal of taking advantage of the properties of ILs in materials, their liquid nature limits their use due to shaping necessities in most devices as a result of possible leakages and miniaturization impediments. Thus, regardless of the pursued application, taking advantage of IL properties in solid-state materials remains a major challenge. To this aim, several approaches are under investigation through grafting on supports, swelling in polymers and impregnation on preliminary prepared oxide particles. Despite these research fields there are still problems associated with stabilization of ionic liquids within a solid form.
For these reasons and others there is a need for ionic liquids in stabilised forms.